Proper Drill Bit Placement.

[MP63]

This may sound like a silly question, but is there a proper way to mount a drill bit onto a drill press chuck?

The reason I ask is, I was tring to drill to very close tolerances, such as a 17/64" hole, and found that the hole was not quite the same size. It came out slighly different everytime, no matter which hole I used to tighten the chuck. So, the drilled hole ended up too big on the final, actual hole. Hmmm????

I noticed the bit would wobble at the tip every time I remounted it.

What's the key to this simple yet, puzzling delima?

Thanks,

Mike

[Hydrogeoman]

I was taught to snug the bit up in the chuck by hand and then use the chuck key in each of the holes, snugging it up a little bit in each hole until it is good and tight. Kind of like tightening lug nuts on a wheel. The idea being that the jaws on the chuck will tighten equally around the drill bit.

The other problem you may be having though is a slightly bent drill bit.

[thegarehanman]

Is it a fairly low end drill press? This may just be the result of a fair amount of runout.

peace,

russ

[MiKro]

This may sound like a silly question, but is there a proper way to mount a drill bit onto a drill press chuck?

The reason I ask is, I was tring to drill to very close tolerances, such as a 17/64" hole, and found that the hole was not quite the same size. It came out slighly different everytime, no matter which hole I used to tighten the chuck. So, the drilled hole ended up too big on the final, actual hole. Hmmm????

I noticed the bit would wobble at the tip every time I remounted it.

What's the key to this simple yet, puzzling delima?

Thanks,

Mike

HG is correct with the method he described for proper drill chuck tightening, Your problem is more characteristic of what Russ described though. Either a bent bit or runout on the drill press.

MK

[MP63]

I bought the drill press used.

It is a Delta from the 50's. It is solid steel throughout.

The shop said that they replaced/rebuilt the Jacobs chuck.

Simple set ups but runs great.

What is runout?

Mike

[soapbarstrat]

Is it an "import" drill bit (import as in mysterious far East) ?

I have a set of Chinese drill bits that have several warped bits in the set. One of the big ones is warped so bad, it makes my drill press dance. It's a fairly big floor mount drill press and that sucker almost teeter-tottered from side to side until it was going to fall over. I had to hold on to the drill press like I was madly in love with it, while forcing it not to fall and trying to use one hand to turn it off !

(But it wouldn't be too bad, if I was madly in love with it. Not a bad looking drill press) :

http://img.photobucket.com/albums/v398/soa...lpress11061.jpg

You need to rig up a DI to check the run-out.

Here's the funny thing about this coming up. About 3 years ago, I loaned my DP to a carpenter/electrician friend for 6 months while I was out of town. I took the press to his house.

In order to get it in the box (because I'm real **** and keep the damn box in case I have to transport it, plus the box has styrofoam molded compartments for the various parts of the DP), I have to take most of it apart.

So, when I finally get it back home, and re-assembled, I notice after a while the holes drilled are bigger than the drill bit size, etc. And I make the mistake of assuming carpenter friend was a little brutal with my DP (since he did manage to break all the magnetic "attachments" I have on the DP for holding different things onto the DP), and thought he must have worn the bearings to the point where I now have a lot of run-out.

(luckily I never said a word about it to him).

Now, that's a long time ago. Just recently, I decided to make my own Sperzel tuner pin hole drilling jig. This requires very precise hole drilling, which just wasn't happening for me.

Also, the jaws on the chuck were now getting stuck quite often.

Because of both problems, I decided to take the chuck off again, at least to possibly help with the jaws getting stuck. Compressed air, Tri-Flow, etc, took care of it, BUT, when I knocked the chuck back into the spindle, then rigged the DI back up to check for run-out, I was now down to .0015" run-out.

I then went back to making the Sperzel jig and it turned out GREAT :

http://img.photobucket.com/albums/v398/soa...l_jig11061b.jpg

http://img.photobucket.com/albums/v398/soa...l_macstrat2.jpg

Oh yeah, right after I got the run-out down to minimum, I celebrated by buying a 115 piece 'made in USA by Triumph drill company' set of bits for $177.00

DI = Dial Indicator

Run out= how much chuck, spindle, or bit, is off-center, or something like that.

Edited December 5, 2006 by soapbarstrat

[MP63]

Thanks for the info.

I may need to remove it and check it out. The drill press is just massive in weight and so solid.

I was drilling the stud holes for a Schaller roller bridge. The test hole came out great with the 17/64" bit.

The real hole was a bit bigger. No consistency on the chuck.

The longer bits really show the wobble. Multiple tries at remounting seem to help a bit.

I was using a German made brad point bit. Tell me about the crooked import bits!

I just need to finish up some "non-critical" drilling, then I'll have a go at it.

I used to use the drill press with sanding drums. I wonder if that screwed it up?

Hopefully, the finish will snug the bridge stud up, or I can use Titebond to swell the wood and lock it in nice and tight.

Thank you,

Mike

[postal]

Only thing I want to add, is drilling mutliple holes, clean the dust off the drill bit after each hole. Woods like maple leave almost no dust, but rosewood/ebony leave a lot of dust on the bit.

If you dont clean off this dust, it can make a hole larger than it's supposed be.

Just use a scrap block of non oily wood like maple, and lightly press it to the bit will usually knock the dust out of the flutes.